Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil. I. Host-fungus compatibility

The effects of inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on two peanut (Arachis hypogaea L.) cultivars, a traditional, low-yielding Mozambican landrace (Local) and a modern, high-yielding cultivar (Falcon), were tested in a non-sterile and low-fertile Mozambican soil. Host-fungus compatibility was determined as a percentage of root colonization in combination with the effects on plant-growth parameters, nodulation, and yield. Mycorrhizal colonization increased with inoculation, particularly in cultivar Falcon with the commercial inoculant. The differences in root colonization were reflected in plant growth responses as changes in leaf and root biomass, leaf-area ratio, nodulation, and yield components. The peanut landrace Local seemed to be more compatible with the indigenous AM fungi, whereas the modem cultivar Falcon responded best to the commercial inoculant. The results encourage the use of mycorrhizae as a biological tool for increasing production of peanut in low-fertile tropical soils. Inoculation may compensate for low soil fertility, particularly for cultivars that are bred for high yields, are under high fertilization, and are not adapted to the indigenous AM fungi. For peanut landraces, on the other hand, adequate management of the indigenous AM potential seems to be a more appropriate course.